SugarDB/internal/volumes/modules/js/example.js

// The keyword to trigger the command
var command = "JS.EXAMPLE"

// The string array of categories this command belongs to.
// This array can contain both built-in categories and new custom categories.
var categories = ["generic", "write", "fast"]

// The description of the command.
var description = "(JS.EXAMPLE) Example JS command that sets various data types to keys"

// Whether the command should be synced across the RAFT cluster.
var sync = true

/**
 *  keyExtractionFunc is a function that extracts the keys from the command and returns them to SugarDB.keyExtractionFunc
 *  The returned data from this function is used in the Access Control Layer to determine if the current connection is
 *  authorized to execute this command. The function must return a table that specifies which keys in this command
 *  are read keys and which ones are write keys.
 *  Example return: {readKeys: ["key1", "key2"], writeKeys: ["key3", "key4", "key5"]}
 *
 *  1. "command" is a string array representing the command that triggered this key extraction function.
 *
 *  2. "args" is a string array of the modifier args that were passed when loading the module into SugarDB.
 *  These args are passed to the key extraction function everytime it's invoked.
*/
function keyExtractionFunc(command, args) {
  if (command.length > 1) {
    throw "wrong number of args, expected 0"
  }
  return {
    readKeys: [],
    writeKeys: []
  }
}

/**
 * handlerFunc is the command's handler function. The function is passed some arguments that allow it to interact with
 * SugarDB. The function must return a valid RESP response or throw an error.
 * The handler function accepts the following args:
 *
 * 1. "context" is a table that contains some information about the environment this command has been executed in.
 *     Example: {protocol: 2, database: 0}
 *     This object contains the following properties:
 *     i) protocol - the protocol version of the client that executed the command (either 2 or 3).
 *     ii) database - the active database index of the client that executed the command.
 *
 * 2. "command" is the string array representing the command that triggered this handler function.
 *
 * 3. "keyExists" is a function that can be called to check if a list of keys exists in the SugarDB store database.
 *     This function accepts a string array of keys to check and returns a table with each key having a corresponding
 *     boolean value indicating whether it exists.
 *     Examples:
 *     i) Example invocation: keyExists(["key1", "key2", "key3"])
 *     ii) Example return: {key1: true, key2: false, key3: true}
 *
 * 4. "getValues" is a function that can be called to retrieve values from the SugarDB store database.
 *     The function accepts a string array of keys whose values we would like to fetch, and returns a table with each key
 *     containing the corresponding value from the store.
 *     The possible data types for the values are: number, string, nil, hash, set, zset
 *     Examples:
 *     i) Example invocation: getValues(["key1", "key2", "key3"])
 *     ii) Example return: {key1: 3.142, key2: nil, key3: "Pi"}
 *
 * 5. "setValues" is a function that can be called to set values in the active database in the SugarDB store.
 *     This function accepts a table with keys and the corresponding values to set for each key in the active database
 *     in the store.
 *     The accepted data types for the values are: number, string, nil, hash, set, zset.
 *     The setValues function does not return anything.
 *     Examples:
 *     i) Example invocation: setValues({key1: 3.142, key2: nil, key3: "Pi"})
 *
 * 6. "args" is a string array of the modifier args passed to the module at load time. These args are passed to the
 *    handler everytime it's invoked.
 */
function handlerFunc(ctx, command, keysExist, getValues, setValues, args) {
  // Set various data types to keys
  var keyValues = {
    "numberKey": 42,
    "stringKey": "Hello, SugarDB!",
    "floatKey": 3.142,
    "nilKey": null,
  }

  // Store the values in the database
  setValues(keyValues)

  // Verify the values have been set correctly
  var keysToGet = ["numberKey", "stringKey", "floatKey", "nilKey"]
  var retrievedValues = getValues(keysToGet)

  // Create an array to track mismatches
  var mismatches = [];
  for (var key in keyValues) {
    if (Object.prototype.hasOwnProperty.call(keyValues, key)) {
      var expectedValue = keyValues[key];
      var retrievedValue = retrievedValues[key];
      if (retrievedValue !== expectedValue) {
        var msg = "Key " + key + ": expected " + expectedValue + ", got " + retrievedValue
        mismatches.push(msg);
        console.log(msg)
      }
    }
  }

  // If mismatches exist, return an error
  if (mismatches.length > 0) {
    throw "values mismatch"
  }

  // If all values match, return OK
  return "+OK\r\n"
}